Measurement of Thermo Physical Properties of Metallic Nanofluids for High Temperature Applications

Abstract

This article presents the measurement of thermal conductivity and viscosity of nanofluids experimentally. Silver nanoparticles dispersed in water with volume concentrations of 0.3, 0.4, 0.6, 0.8, 0.9, and 1.2 vol% are used in the present study. A transient hot-wire apparatus is used for measuring the thermal conductivity of nanofluids and a Cannon-Fenske viscometer is used to measure the kinematic viscosity of nanofluids. The data are collected for temperatures ranging from 50 to 90°C. The results have shown an increase in the measured thermal conductivity and viscosity of nanofluids as the particle concentrations increase, and the values are higher than the values of the base liquids. The minimum enhancement of 27% for 0.3 vol% and a maximum enhancement of 115% for 1.2 vol% are observed at an average temperature of 70°C when compared with pure water for the same temperature. Further, the thermal conductivity of nanofluids increases with the increase in nanofluid temperatures and, conversely, the viscosity of nanofluids decreases with the increase in temperature of nanofluids. An experimental correlation is developed based on the experimental data for thermal conductivity and viscosity that relates the particle volume concentration and nanofluid temperature.